Link to home

Genomic insights into the mechanisms of pathogenesis in Raffaelea lauricola, causal agent of laurel wilt disease

Yucheng Zhang: Department of Plant Pathology, University of Florida

<div>Laurel wilt, caused by <em>Raffaelea lauricola</em>, is a lethal vascular disease of North American members of the Lauraceae plant family. <em>R. lauricola</em> and its primary ambrosia beetle vector <em>Xyleborus glabratus </em>are invasive introductions from Asia. However, there is no report of laurel wilt killing native Lauraceae trees in Asia. To gain insight into the lethality of <em>R. lauricola</em> in North America, we generated and compared high quality genomes of <em>R. lauricola </em>and the closely related, nonpathogenic <em>R. aguacate</em>, each of which are symbionts of ambrosia beetles associated with avocado. The <em>R. lauricola</em> genome uniquely encodes small-secreted proteins (SSPs) that are associated with virulence in other pathogens and is enriched in secondary metabolite biosynthetic clusters. The two species also exhibit significant differences in CAZymes that are associated with plant polysaccharide degradation, such as CBM50 (LysM) and CH18. Notably, fungal-secreted LysMs have been reported as a novel class of conserved effectors. We have identified potential adaptations of <em>R. lauricola</em>, which may have enabled it to colonize and cause disease on host plants; pathogen-specific SSPs, secondary metabolites, and LysM effectors are candidate factors for this adaption. Functional analysis of these candidate virulence factors is in progress to gain insight into the mechanisms of pathogenesis in <em>R. lauricola</em>.</div>